Session: 07-02: Experiments and Analyses - I

Paper Number: 133818

133818 - Experimental Study of the Effect of Inclination Angle on the Heat Transfer Characteristics of Steam Condensation in the Vertical Tube 

Abstract: 

In-tube condensation heat exchangers, known for their high heat transfer capacity, find extensive use in diverse energy applications. Their significance is particularly pronounced in safety systems within nuclear power plants, such as passive residual heat removal systems (PRHRS) in offshore floating nuclear power plants. To investigate the transient heat transfer characteristics of vertical in-tube condensation under rolling conditions, with a maximum rolling amplitude of 20°, a prerequisite is to delve into the steady-state heat transfer characteristics of condensation under stationary conditions. In the past decades, a large number of experimental studies for heat transfer characteristics of condensation in tubes under stationary conditions had been presented. However, the heat transfer characteristics of steam condensation in inclined tubes remained poorly investigated. Therefore, the purpose of the experiment was to investigate the effect of inclination angle on steam condensation heat transfer characteristics for downward flow in a vertical tube at different mass fluxes. The inlet pressure of saturated steam was 0.2 MPa and the mass fluxes ranged from 20 to 60 kg·m^-2·s^-1. The experiment was conducted at a range of inclination angles between 0° to 20°. The results showed that with the variation of inclination angle, the film flow patterns in the tube at the outlet of the condensation tube mainly showed three kinds of type, namely, annular flow, semi-annular flow and stratified wavy flow. The liquid film flow pattern in the tube was directly influenced by variations in mass flux and steam quality. As the mass flux was increased, the circumferential distribution characteristics of the liquid film flow pattern in the tube were weakly affected by the inclination effect. Conversely, the transition of the liquid film flow pattern inside the tube became more susceptible to this effect as the steam quality decreased. The temperatures of the outer wall of the condenser tube were investigated, revealing that the inclination angle effect induced differences between the upper and lower wall temperatures. The trend became more pronounced with an increase in the inclination angle. Simultaneously, the heat transfer coefficient experienced an increase with the inclination angle, and the impact of the inclination angle on the heat transfer coefficient diminished with an increase in mass flux. The decrease of the quality of the steam would lead to the decrease of the condensation heat transfer coefficient, and the influence of the angle of inclination on the condensation heat transfer coefficient increased. Comparing the heat transfer coefficients measured experimentally with the calculated values of the relational equation of Shah (2016), the results showed that the precision of the predicted values of the relational equation of Shah for the heat transfer coefficients of condensation in the vertical tube was good enough.

Presenting Author: Jiabao LIU Harbin Engineering University

Presenting Author Biography: Mainly engaged in experimental research on condensation heat transfer of steam in heat exchange tubes, numerical simulation of multiphase flow in computational fluid dynamics, and measurement of multiphase flow parameters.

Authors:

Jiabao LIU Harbin Engineering University
Xiaxin Cao Harbin Engineering University
Peixun Yang Harbin Engineering University